Fuel Tank Vent Blockage

The port vent line had a low point (i.e. p-trap) where it penetrated into the bilge. Drilled 3/16" holes in the floor joists and then nylon-tied the 3/4" vent hose tightly to the bottom of the joist. Had to replace the 1100 gpm main bilge pump as one of the plastic tabs which held it into the strainer had broken off.